Organopolysiloxanes having aliphatically unsaturated radicals, the preparation thereof and the use thereof in crosslinkable materials

ABSTRACT

The invention relates to organopolysiloxanes which have aliphatically unsaturated radicals, are soluble to at least 80 wt % in organic solvents selected from xylene and toluol at a temperature of 25° C. and a pressure of from 900 to 1100 hPa and contain at least one unit of the following formula (I) R 1   a  R 2-a  SiO 2/2 , at least one unit of the following formula (II) R 1   b  R 3-b  SiO 1/2 , at least one unit of the following formula (III) O 1/2  R 2  SiO x  YRSiO 2/2 , and optionally at least one unit of the following formula (IV) O 1/2  R 2  SiO x  YR 2  SiO 1/2 , in which: 
     R can be identical or different and is a monovalent, substituted or unsubstituted, SiC-bonded, aliphatically saturated hydrocarbon radical. 
     R 1  can be identical or different and is a monovalent, SiC-bonded, substituted or unsubstituted, aliphatically unsaturated hydrocarbon radical, 
     a is 0, 1 or 2, 
     b is 0, 1, 2 or 3, 
     x is 0 or 1 and 
     y is a radical --(CR 3   2 ) n  CHR 3  -- with at least two carbon atoms, where n is 0 or an integer from 1 to 3 and R 3  is a hydrogen atom or is as defined for R, 
     with the proviso that the organopolysiloxane includes at least one unit of the formula (II) where b is not 0. It also relates to the preparation of the organopolysiloxanes and the use thereof in crosslinkable materials.

TECHNICAL FIELD

The invention relates to organopolysiloxanes which contain aliphaticallyunsaturated radicals and are soluble in organic solvents, to processesfor their preparation and to their use in crosslinkableorganopolysiloxane compositions, especially for producingadhesive-repellent organopolysiloxane films.

BACKGROUND OF THE INVENTION

EP 0403890 B1 (Bayer AG; published on Mar. 16, 1994) or thecorresponding U.S. Pat. No. 5,077,369, and EP 0640662 A2 (Bayer AG;published on Mar. 1, 1995), describe addition-crosslinkingorganopolysiloxane mixtures for producing adhesion-reducing coatings.The organopolysiloxanes present in the mixtures are branched, with thebranching sites being constituted by trifunctional monoorganosiloxygroups, so-called T units, or tetrafunctional siloxy groups, so-called Qunits, and the organopolysiloxanes described have at least 12 T unitsper molecule. Moreover, they possess triorganosiloxy groups, so-called Munits, some of which are free from unsaturated radicals while theremainder carry only one unsaturated radical each. Theorganopolysiloxanes are prepared by hydrolyzing chlorosilanes and thencarrying out polymerization with low molecular mass cyclicdiorganopolysiloxanes. U.S. Pat. No. 4,772,515 (Shin-Etsu Chemical Co.;published on Sep. 20, 1988) likewise claims addition-crosslinkingorganopolysiloxane mixtures for producing adhesive-repellentorganopolysiloxane coatings. The organopolysiloxanes present have atleast two branching sites per molecule, in the form of T units, and eachterminal Si atom possesses at least one unsaturated group. Theorganopolysiloxanes are prepared by reacting alkyltrimethoxysilanes withoctamethylcyclotetrasiloxane in the presence of a basic catalyst,followed by hydrolysis and reaction with alkenyldisiloxanes.

SUMMARY OF THE INVENTION

The invention provides organopolysiloxanes containing aliphaticallyunsaturated radicals, which are soluble in organic solvents selectedfrom the group consisting of xylenes and toluene to an extent of atleast 80 percent by weight, preferably 90 percent by weight,particularly preferably 100 percent by weight, at a temperature of 25°C. and a pressure of from 900 to 1100 hPa, and comprise at least oneunit of the formula

    R.sup.1.sub.a R.sub.2-a SiO.sub.2/2                        (I),

at least one unit of the formula

    R.sup.1.sub.b R.sub.3-b SiO.sub.1/2                        (II),

at least one unit of the formula

    O.sub.1/2 R.sub.2 SiO.sub.x YRSiO.sub.2/2                  (III)

and, if desired, at least one unit of the formula

    O.sub.1/2 R.sub.2 SiO.sub.x YR.sub.2 SiO.sub.1/2           (IV),

where

R can be identical or different and is a monovalent, substituted orunsubstituted, SiC-bonded, aliphatically saturated hydrocarbon radical,

R¹ can be identical or different and is a monovalent, SiC-bonded,substituted or unsubstituted, aliphatically unsaturated hydrocarbonradical,

a is 0, 1 or 2, preferably 0,

b is 0, 1, 2 or 3, preferably 0 or 1,

x is 0 or 1, preferably 0, and

Y is a radical --(CR³ ₂)_(n) CHR³ -- with at least two carbon atoms,where n is 0 or an integer from 1 to 3, particularly preferably 0 or 1,and R³ is a hydrogen atom or is as defined for R,

with the proviso that the organopolysiloxane includes at least one unitof the formula (II) where b is not 0.

In addition to the units of the formula (I), (II), (III) and ifappropriate (IV) the novel organopolysiloxanes may have further siloxaneunits, for example those of the formula O_(2/2) RSiO_(x) YRSiO_(2/2) andO_(2/2) RSiO_(x) YR₂ SiO_(1/2), although this is not preferred.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The term organopolysiloxanes is intended in the context of the presentinvention to embrace not only polymeric but also dimeric and oligomericsiloxanes.

The novel organopolysiloxanes preferably include at least two units ofthe formula (II) where b=1.

The radical R preferably comprises substituted or unsubstituted,monovalent, SiC-bonded, aliphatically saturated hydrocarbon radicalshaving 1 to 18 carbon atoms.

Examples of each radical R are alkyl radicals such as the methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl,neopentyl and the tert-pentyl radicals, hexyl radicals, such as then-hexyl radical, heptyl radicals, such as the n-heptyl radical, octylradicals, such as the n-octyl radical and isooctyl radicals, such as the2,2,4-trimethylpentyl and the 2-ethylhexyl radical, nonyl radicals, suchas the n-nonyl radical, decyl radicals, such as the n-decyl radical,dodecyl radicals, such as the n-dodecyl radical, tetradecyl radicals,such as the n-tetradecyl radical, hexadecyl radicals, such as then-hexadecyl radical, and octadecyl radicals, such as the n-octadecylradical, cycloalkyl radicals, such as cyclopentyl, cyclohexyl and4-ethylcyclohexyl radical, cycloheptyl radicals, norbornyl radicals andmethylcyclohexyl radicals, aryl radicals, such as the phenyl, biphenyl,naphthyl and anthryl and phenanthryl radical; alkaryl radicals, such aso-, m-, p-tolyl radicals, xylyl radicals and ethylphenyl radicals;aralkyl radicals, such as the benzyl radical, and also the α- and theβ-phenylethyl radical.

Examples of substituted hydrocarbon radicals as radical R arehalogenated hydrocarbon radicals, such as the chloromethyl,3-chloropropyl, 3,3,3-trifluoropropyl and5,5,5,4,4,3,3-heptafluoropentyl radical, and the chlorophenyl,dichlorophenyl and trifluorotolyl radical, and also cyanoalkyl radicals,such as the 2-cyanoethyl and 3-cyanopropyl radical.

The radical R is particularly preferably the methyl, n-decyl, n-dodecyl,n-tetradecyl, n-hexadecyl and n-octadecyl radical, especially the methylradical and the n-dodecyl radical.

Radical R¹ preferably comprises alkenyl radicals having 2 to 20 carbonatoms, particularly preferably those with a terminal carbon-carbondouble bond, especially the vinyl radical.

Examples of radical R¹ are alkenyl radicals, such as the vinyl, allyl,allyloxy, CH₂ ═CH--(CH₂)₂ --, CH₂ ═CH--(CH₂)₃ --, CH₂ ═CH--(CH₂)₄ --,CH₂ ═CH--(CH₂)₅ --, CH₂ ═CH--(CH₂)₆ --, 4-vinylcyclohexyl and3-norbornenyl radical.

Radical R³ is particularly preferably hydrogen atom and the methylradical, especially hydrogen atom.

Radical Y is preferably --CH₂ --CH₂ -- or --CH(CH₃)--.

In particular, in the novel organopolysiloxanes, at least 70% of allSiC-bonded radicals are methyl groups.

The novel organopolysiloxanes have a viscosity at 25° C. of preferablyfrom 5 to 500,000 mm² /s, particularly preferably from 10 to 20,000 mm²/s.

The novel organopolysiloxanes preferably have iodine numbers between 0.5and 20, the iodine number indicating the quantity of iodine in gramsconsumed in the course of addition onto the double bond per 100 grams ofemployed material to be analyzed.

The novel organopolysiloxanes have the advantage that they possess alower viscosity than linear organosiloxanes of comparable molecularweight.

The novel organopolysiloxanes also have the advantage that they are ofhighly stable viscosity on storage.

The novel organopolysiloxanes can be prepared by any desired methods.

The present invention additionally provides a process for preparing thenovel organopolysiloxanes, which comprises reacting linearorganosiloxanes A consisting of at least one unit of the formula

    R.sup.4.sub.c R.sup.5.sub.2-c SiO.sub.2/2                  (V),

and/or at least one unit of the formula

    R.sup.4.sub.d R.sup.5.sub.3-d SiO.sub.1/2                  (VI),

where

R⁴ can be identical or different and is as defined for R¹,

R⁵ can be identical or different and is as defined for R,

c is 0, 1 or 2, preferably 0, and

d is 0, 1, 2 or 3, preferably 0 or 1,

with the proviso that organosiloxanes A possess at least one radical R⁴and that there is at least one organosiloxane A having 2 units of theformula (VI) where d is not 0, with linear or cyclic organosiloxane Bconsisting of at least one unit of the formula

    H.sub.f R.sup.7.sub.g R.sup.6.sub.3-f-g SiO.sub.1/2        (VIII),

and/or at least one unit of the formula

    H.sub.e R.sup.6.sub.2-e SiO.sub.2/2                        (VII),

where

R⁶ can be identical or different and is as defined for R,

R⁷ is as defined for R¹,

e is 0 or 1,

f is 0 or 1, and

g is 0, 1, 2 or 3, preferably 0,

with the proviso that the sum g+f is less than or equal to 3 and thatorganosiloxane B has at least one unit of the formula (VII) where e is1, and, if desired, with hydrocarbons C containing aliphaticcarbon-carbon multiple bonds and, if desired, in the presence of inertorganic solvent D, in the presence of a catalyst E which promotes theaddition of Si-bonded hydrogen onto aliphatic multiple bond, with theproviso that in the unreacted mixture of starting materials the molarratio of the units of the formula (VI) where d is not 0 to the Si-bondedhydrogen atoms present in the units of the formula (VII) is at least1.3:1, preferably at least 1.5:1.

The components employed in the novel process may each comprise one kindof this component or else various kinds of such components.

The organosiloxanes A employed in the novel process are preferably thosecomprising units of the formula (V) where c=0 and units of the formula(VI), with the proviso that the organosiloxanes A possess at least oneunit of the formula (VI) where d is not 0 and that there is at least oneorganosiloxane A having 2 units of the formula (VI) where d is not 0.

With particular preference, the organosiloxanes A employed in the novelprocess are 1,3-divinyl-1,1,3,3-tetramethyldisiloxane,vinylpentamethyldisiloxane, copolymers of vinyldimethylsiloxane anddimethylsiloxane units, and copolymers of vinyldimethylsiloxane,trimethylsiloxane and dimethylsiloxane units, with the proviso thatthere is at least one organosiloxane A having 2 units of the formula(VI) where d is not 0 in the reaction mixture.

The abovementioned copolymers have a viscosity of preferably from 1 to20,000 mm² /s, particularly preferably from 2 to 5,000 mm² /s at 25° C.,and an iodine number of preferably from 0.5 to 100, particularlypreferably from 2 to 80.

In particular, the organosiloxanes A employed in the novel process arecopolymers of vinyldimethylsiloxane and dimethylsiloxane units.

Preferably, the linear organosiloxanes B employed in the novel processare copolymers of dimethylhydridosiloxane, dimethylsiloxane andmethylhydridosiloxane units, copolymers of trimethylsiloxane,dimethylsiloxane and methylhydridosiloxane units, copolymers oftrimethylsiloxane, dimethylhydridosiloxane, dimethylsiloxane andmethylhydridosiloxane units, copolymers of vinyldimethylsiloxane,dimethylsiloxane and methylhydridosiloxane units having a viscosity ofpreferably from 2 to 20,000 mm² /s, particularly preferably from 3 to5,000 mm² /s, at 25° C.

Preferably, the cyclic organosiloxanes B employed in the novel processare 1,3,5,7-tetramethyltetrahydridocyclotetrasiloxane and1,3,5,7,9-pentamethylpentahydridocyclopentasiloxane.

With particular preference, the organosiloxanes B employed in the novelprocess are copolymers of dimethylhydridosiloxane, dimethylsiloxane andmethylhydridosiloxane units and copolymers of trimethylsiloxane,dimethylsiloxane and methylhydridosiloxane units.

Preferably, the organosiloxanes B employed in accordance with theinvention contain on average at least two units of the formula (VII)where e=1.

The siloxanes A and B employed in accordance with the invention arecommercially available products and/or can be prepared by methods whichare customary in silicon chemistry.

The hydrocarbons C which have aliphatic carbon-carbon multiple bonds andare employed if desired in the novel process are preferably 1-alkeneshaving 10 to 18 carbon atoms, such as 1-decene, 1-dodecene,1-tetradecene, 1-hexadecene and 1-octadecene, with particular preferencebeing given to 1-dodecene and 1-tetradecene.

If component C is employed in the novel process, then the quantitiesinvolved are such that the molar ratio of the carbon-carbon multiplebonds of component C to Si-bonded hydrogen in the units of the formula(VII) is not more than 0.5.

The inert organic solvents D employed if desired in the novel processare preferably toluene, xylenes, tetrahydrofuran and cyclohexane.

If inert organic solvent is used in the novel process, then thequantities involved are preferably from 5 to 200 percent by weight,particularly preferably from 10 to 150 percent by weight, based in eachcase on the overall weight of organosiloxane A and organosiloxane B.

As catalysts E which promote the addition of Si-bonded hydrogen ontoaliphatic multiple bond, it is possible in the novel process to employthe same catalysts which it has also been possible to employ to date topromote the addition of Si-bonded hydrogen onto aliphatic multiple bond.The catalysts preferably comprise a metal from the group of the platinummetals or a compound or a complex from the group of the platinum metals.

Examples of such catalysts are metallic and finely divided platinum,which may be on supports such as silica, alumina or activated charcoal,compounds or complexes of platinum, such as platinum halides, forexample PtCl₁, H₂ PtCl₆.6H₂ O, Na₂ PtCl₄.4H₂ O, platinum-olefincomplexes, platinum-alcohol complexes, platinum-alcoholate complexes,platinum-ether complexes, platinum-aldehyde complexes, platinum-ketonecomplexes, including reaction products of H₂ PtCl₆.6H₂ O andcyclohexanone, platinum-vinylsiloxane complexes, such asplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complexes with orwithout a content of detectable inorganically bonded halogen,bis-(γ-picoline)platinum dichloride, trimethylenedipyridineplatinumdichloride, dicyclopentadieneplatinum dichloride, dimethylsulfoxide-ethyleneplatinum(II) dichloride, cyclooctadiene-platinumdichloride, norbornadiene-platinum dichloride, γ-picoline-platinumdichloride, cyclopentadiene-platinum dichloride and reaction products ofplatinum tetrachloride with olefin and primary amine or secondary amineor primary and secondary amine in accordance with U.S. Pat. No.4,292,434, such as the reaction product of platinum tetrachloride,dissolved in 1-octene, with sec-butylamine, or ammonium-platinumcomplexes according to EP-B 110 370.

In the novel process catalyst E is preferably employed in quantities offrom 0.5 to 500 ppm by weight (parts by weight per million parts byweight), particularly preferably in quantities of from 1 to 40 ppm byweight, calculated in each case as elemental platinum and based on theoverall weight of organosiloxane A and organosiloxane B.

The novel process is preferably carried out at the pressure of thesurrounding atmosphere, i.e. at about 1,000 hPa. However, it can also becarried out at higher and lower pressures. In addition, the novelprocess is preferably carried out at a temperature of from 50 to 150°C., particularly preferably from 70 to 120° C.

In the novel process the starting materials can be introduced in anyorder and then brought to reaction by heating.

For example, the novel process can be carried out by initially chargingthe organosiloxane A, catalyst E and if used, inert organic solvent D tothe reaction vessel, then heating the mixture and subsequently meteringin, slowly, the organosiloxane B.

If terminally unsaturated hydrocarbon C is used in the novel process, itis preferably first reacted with organosiloxane B in the presence ofcatalyst E and, if used, solvent D, and only then is organosiloxane Aadded to the reaction mixture for the subsequent reaction.

Preferably, when the novel reaction is over, any volatile constituentsstill present, such as organosilicon compounds, hydrocarbon C andorganic solvents, are removed, preferably by distillation at a pressurewhich is preferably from 5 hPa to the pressure of the surroundingatmosphere and at a temperature of from 80 to 180° C.

The reaction product obtained by the novel process may include, inaddition to the novel organopolysiloxanes, organosiloxanes A inquantities of preferably from 0 to 30 percent by weight, particularlypreferably from 0 to 20 percent by weight, based in each case on theoverall weight of reaction product.

The novel process has the advantage that it is possible, simply and withhigh reproducibility, to prepare branched organopolysiloxanes with avariable degree of branching which are soluble in organic solvents.

The novel process has the advantage that organopolysiloxanes of definedstructure, i.e. with a defined number and type of end groups and adefined mean number of siloxane units between the branching sites anddefined mean number of siloxane units in the side chains, can beprepared in a simple manner.

The novel process also has the advantage that it is possible to preparenovel organopolysiloxanes in which the branching sites are evenlydistributed.

The novel organopolysiloxanes or those prepared in accordance with theinvention can be employed for all purposes for which organopolysiloxaneswith aliphatically unsaturated radicals have also been used to date.

They are particularly suitable for the preparation of crosslinkableorganopolysiloxane compositions, preferably for the production ofcoatings which repel tacky substances.

The present invention additionally provides crosslinkableorganopolysiloxane compositions which comprise

(1) novel organopolysiloxanes or organopolysiloxanes prepared inaccordance with the invention,

(2) organosiloxanes containing Si-bonded hydrogen,

(3) catalysts which promote the addition of Si-bonded hydrogen ontoaliphatic multiple bond

and, if desired, further substances.

The components (2) and (3) and any further substances employed can bethe same as those which it has been possible to employ to date incompositions which can be crosslinked by the addition of Si-bondedhydrogen onto aliphatic carbon-carbon multiple bond.

As organosiloxanes (2) containing Si-bonded hydrogen atoms it ispreferred to employ linear, cyclic or branched organopolysiloxanescomprising units of the formula ##EQU1## where R⁸ can be identical ordifferent and is as defined above for R,

h is 0, 1, 2 or 3, and

i is 0, 1 or 2,

with the proviso that the sum of h+i is less than or equal to 3 and thatthere are on average at least two Si-bonded hydrogen atoms per molecule.

Although not expressed by formula (IX), up to 8% of the radicals R⁸ inthe organopolysiloxane (2) can also have the meaning of alkoxy radical.

The organosiloxanes (2) preferably have an average viscosity of from 5to 1,000 mm² /s, particularly preferably from 10 to 500 mm² /s, at 25°C.

Preferably, at least 50% of all SiC-bonded radicals or organosiloxane(2) are methyl radicals.

The organosiloxane (2) employed in accordance with the inventionpreferably contains on average at least 3 Si-bonded hydrogen atoms permolecule.

The organosiloxane (2) employed in accordance with the inventionpreferably contains Si-bonded hydrogen in quantities of from 0.1 to 2percent by weight, particularly preferably from 0.5 to 1.7 percent byweight, based in each case on the weight of the organopolysiloxane (2).

Organopolysiloxane (2) preferably comprises copolymers ofdimethylhydridosiloxane, methylhydridosiloxane, dimethylsiloxane andtrimethylsiloxane units, copolymers of trimethylsiloxane,dimethylhydridosiloxane and methylhydridosiloxane units, copolymers oftrimethylsiloxane, dimethylsiloxane and methylhydridosiloxane units,copolymers of methylhydridosiloxane and trimethylsiloxane units,copolymers of methylhydridosiloxane, diphenylsiloxane andtrimethylsiloxane units, copolymers of methylhydridosiloxane,dimethylhydridosiloxane and diphenylsiloxane units, copolymers ofmethylhydridosiloxane, phenylmethylsiloxane, trimethylsiloxane anddimethylhydridosiloxane units, copolymers of methylhydridosiloxane,dimethylsiloxane, diphenylsiloxane, trimethylsiloxane and/ordimethylhydridosiloxane units and also copolymers ofdimethylhydridosiloxane, trimethylsiloxane, phenylhydridosiloxane,dimethylsiloxane and/or phenylmethylsiloxane units.

Organopolysiloxane (2) particularly preferably comprises copolymers oftrimethylsiloxane and methylhydridosiloxane units and copolymers oftrimethylsiloxane, dimethylsiloxane and methylhydridosiloxane units.

Organopolysiloxanes (2) are generally known products and/or can beprepared by methods common in silicon chemistry.

In the novel composition siloxane (2) is employed in quantities ofpreferably from 0.7 to 5 mol of Si-bonded hydrogen, particularlypreferably from 1.1 to 3 mol of Si-bonded hydrogen, based in each caseon 1 mol of aliphatic carbon-carbon multiple bond of the novelorganopolysiloxane (1) or the organopolysiloxane (1) prepared inaccordance with the invention.

As catalyst (3) which promotes the addition of Si-bonded hydrogen ontoaliphatic multiple bond it is also possible to employ, in the novelorganopolysiloxane compositions, the same catalysts which it has alsobeen possible to employ to date to promote the addition of Si-bondedhydrogen onto aliphatic multiple bond, the examples and preferredspecies of such substances being those indicated above for catalyst E.

In the novel organopolysiloxane compositions catalyst (3) is preferablyemployed in quantities of from 5 to 500 ppm by weight (parts by weightper million parts by weight), particularly preferably in quantities offrom 10 to 200 ppm by weight, in each case calculated as elementalplatinum and based on the overall weight of novel composition.

In addition to component (1), (2) and (3) the novel organopolysiloxanecompositions can contain compounds (4), so-called inhibitors, whichretard the addition of Si-bonded hydrogen onto aliphatic multiple bond.

Examples of inhibitors (4) which are employed if desired are alkynols,fumaric acid, maleic acid, fumarates and maleates.

In the novel compositions inhibitor (4) is preferably employed inquantities from 0.001 to 5 percent by weight, particularly preferably inquantities of from 0.01 to 1.0 percent by weight, based in each case onthe overall weight of novel composition.

In addition to component (1), (2), (3) and, if used, (4), the novelorganopolysiloxane compositions can contain organopolysilicone resins(5).

The organopolysilicone resins which are used if desired in the novelcompositions as component (5) are preferably so-called MQ resinscomprising units of the formula

    R.sup.9.sub.3 SiO.sub.1/2 and

    SiO.sub.4/2                                                (X),

in which R⁹ can be identical or different and is hydrogen or monovalent,SiC-bonded, substituted or unsubstituted hydrocarbon radical.

Examples of radical R⁹ are hydrogen atom and the examples indicated forradical R and R¹, with preference being given to the methyl radical andthe vinyl radical.

The organopolysiloxane resins (5) employed if desired in the novelcompositions are preferably those according to WO 93/23455(Wacker-Chemie GmbH; published on Nov. 25, 1993) and the Germanapplication P 44 36 817.8 (Wacker-Chemie GmbH; filed on Oct. 14, 1994)or the corresponding US application with the serial number U.S. Ser. No.08/520331, and the German application with the file reference 19502034.0(Wacker-Chemie GmbH; filed on Jan. 24, 1995).

By way of the quantity of organopolysilicone resin (5) it is possible inparticular to regulate the release properties of the novel compositions.Thus, for example, the release values rise as the quantity oforganopolysiloxane resin (5) increases.

If organopolysiloxane resin (5) is used in the novel compositions, thenit is preferably employed in quantities of from 0.5 to 95 percent byweight, particularly preferably in quantities of from 1 to 80 percent byweight, based in each case on the weight of the novel organopolysiloxane(1) or the organopolysiloxane (1) prepared in accordance with theinvention.

The novel organopolysiloxane compositions can additionally compriselinear organopolysiloxane containing aliphatic carbon-carbon multiplebond (6).

The linear organosiloxanes with aliphatic carbon-carbon multiple bond(6) which are employed if desired are preferably the organosiloxanes Adescribed above.

The organosiloxanes (6) are particularly preferably α,ω-divinylpolydimethylsiloxanes having a viscosity of from 20 to 1,000mm² /s at 25° C.

If organosiloxanes (6) are used in the novel compositions, then they areemployed in quantities of from 1 to 40 percent by weight, particularlypreferably in quantities of from 3 to 25 percent by weight, based ineach case on the novel organopolysiloxane (1) or organopolysiloxane (1)prepared in accordance with the invention.

The novel organopolysiloxane compositions can additionally comprisehydrocarbons (7) containing aliphatic carbon-carbon multiple bonds.

The hydrocarbons (7) containing aliphatic carbon-carbon multiple bonds,which are employed if desired, are preferably 1-alkenes having 10 to 14carbon atoms, such as 1-decene, 1-dodecene and 1-tetradecene.

If hydrocarbons (7) containing aliphatic carbon-carbon multiple bondsare used, then they are preferably employed in quantities of from 0.2 to40 percent by weight, particularly preferably in quantities of from 0.5to 25 percent by weight, based in each case on the overall weight ofnovel composition.

In the case of the novel organopolysiloxane compositions it is possibleif desired to use organic solvents. If organic solvents are used, thenthey may be the same as those which it has also been possible to employto date in compositions which can be crosslinked by addition ofSi-bonded hydrogen onto aliphatic carbon-carbon multiple bond.

Examples of such solvents are petroleum spirits, for example alkanemixtures with a boiling range from 80 to 100° C. at the pressure of thesurrounding atmosphere, n-heptane, benzene, toluene and xylenes,halogenated alkanes having 1 to 6 carbon atoms, such as methylenechloride, trichloroethylene and perchloroethylene, ethers, such asdi-n-butyl ether, esters, such as ethyl acetate, and ketones, such asmethyl ethyl ketone and cyclohexanone.

If organic solvents are used in the novel compositions, then they arepreferably employed in quantities of from 5 to 95 percent by weight,particularly preferably in quantities of from 10 to 70 percent byweight, based in each case on the overall weight of novel composition.

The novel crosslinkable organopolysiloxane compositions may additionallycomprise customary and previously known additives, such aspreservatives, colorants, fungicides, plasticizers, etc.

The novel compositions preferably consist of constituents (1), (2), (3)and, if used, one or more of constituents (4), (5), (6), (7), organicsolvent and additives, with particular preference being given to novelcompositions consisting of components (1), (2), (3) and, if used, one ormore of constituents (4), (5) and (6).

The novel organopolysiloxane compositions can also be processed asemulsion or dispersion. If the novel compositions are to be dispersions,it is of course possible to employ the additives which are customary forthe production of dispersions, for example emulsifiers and water, andalso the customary dispersing equipment.

The novel crosslinkable organopolysiloxane compositions can be preparedby any desired, known methods, such as simple mixing of the individualconstituents. When mixing the constituents (1) to (3) and, if used, (4)to (7) and any further substances added, the sequence is not in factcritical, although it has been found in practice to be expedient to addthe catalyst (3) last of all to the mixture of the other constituents.

The novel compositions can also be in the form of a so-called2-component silicone rubber composition. In this case, therefore, thetwo components of the novel silicone rubber compositions may include allconstituents in any desired combinations and proportions, with theproviso that one component does not simultaneously contain theconstituents (1), (2) and (3).

The novel crosslinkable compositions can be employed for all purposesfor which organopolysiloxane compositions which crosslink by addition ofSi-bonded hydrogen onto aliphatic multiple bond have also been employedto date.

The novel compositions are preferably employed for the production ofcoatings, especially coatings which repel tacky substances, such as, forexample, for the production of release coatings against adheringarticles. Thus they are suitable, for example, for the production ofrelease, backing and interleaving papers, including interleaving andrelease papers which are employed in the production of, for example,cast films or decorative films, or of foams, including those made frompolyurethane. The novel compositions are also suitable, for example, forthe production of release, backing and interleaving cards, films andcloths, for treating the reverse sides of self-adhesive tapes orself-adhesive films or the written sides of self-adhesive labels. Thenovel compositions are also suitable for treating packaging material,such as that comprising paper, cardboard boxes, metal foils and drums,for example cardboard, plastic, wood or iron, which is or are intendedfor the storage and/or transportation of tacky goods, such as adhesives,sticky foodstuffs, for example cakes, honey, candies and meat, bitumen,asphalt, greased materials and crude rubber. A further example of theuse of the novel compositions is the treatment of supports for thetransfer of pressure-sensitive adhesive layers in the so-called transferprocess.

The novel compositions are suitable for the production of theself-adhesive materials connected to the release paper, both by theoff-line method and by the in-line method.

The novel crosslinkable compositions can be applied to the surfaces, forinstance the surfaces which are to be made repellent to tackysubstances, in any desired manner which is suitable and widely known forthe production of coatings from liquid substances, for example bydipping, brushing, flow coating, spraying, rolling or printing, forexample by means of an off-set gravure coating apparatus, by knifecoating or doctor-blade coating, or using an airbrush, which ispreferably used when the novel composition is applied in the form of anemulsion or dispersion.

The surfaces which are to be made repellent to tacky substances and canbe treated within the scope of the invention may be surfaces of anysubstances which are solid at room temperature and at from 900 to 1100hPa. Examples of such surfaces are those of paper, wood, cork andpolymer films, for example polyethylene films or polypropylene films,woven and nonwoven cloth of natural or synthetic fibers or glass fibers,ceramic articles, glass, metals, polyethylene-coated paper, and boards,including those of asbestos. The polyethylene mentioned above may ineach case be high-pressure, medium-pressure or low-pressurepolyethylene. The paper may comprise low-grade papers, such as absorbentpapers, including raw--i.e. not pretreated with chemicals and/or withpolymeric natural substances--kraft paper having a weight of from 60 to150 g/m², unsized papers, papers of low freeness value, mechanicalpapers, unglazed or uncalendered papers, papers which are smooth on oneside owing to the use of a dry glazing cylinder during their productionwithout additional complex measures, and are therefore referred to as"machine-glazed papers", uncoated papers or papers produced from wastepaper, i.e. so-called recycled papers. The paper to be treated inaccordance with the invention may, however, also of course comprisehigh-grade papers, such as low-absorbency papers, sized papers, papersof high freeness value, chemical papers, calendered or glazed papers,glassine papers, parchmentized papers or precoated papers. Cards andboards may also be of high or low grade.

The novel crosslinkable organopolysiloxane compositions can becrosslinked in a known manner, during which any terminally unsaturatedhydrocarbon (7) is incorporated chemically into the silicone matrix.

The novel compositions are preferably crosslinked at from 50 to 200° C.,particularly preferably from 60 to 150° C., at a pressure from 900 to1100 hPa. If the novel compositions are crosslinked at relatively lowtemperatures, i.e. in the range from preferably 50 to 110° C., then itis preferred in the novel compositions to employ novelorganopolysiloxanes (1), or organopolysiloxanes (1) prepared inaccordance with the invention, which also include units of the formula(II) where b=0.

Preferred energy sources for crosslinking by heating are ovens, forexample convection ovens, heating tunnels, heated rollers, heated platesor heat rays in the infrared region. The novel compositions can becrosslinked not only by heating but also by irradiation with ultravioletlight or with UV and/or IR light. Ultraviolet light used is commonlythat with a wavelength of 253.7 nm. A host of lamps which emitultraviolet light with a wavelength of from 200 to 400 nm and whichpreferentially emit ultraviolet light with a wavelength of 253.7 nm isavailable commercially.

The novel compositions have the advantage that they crosslink rapidlyeven at relatively low temperatures.

The novel compositions also have the advantage that the resultingcrosslinked organopolysiloxane films possess a high abrasion strength ona wide variety of substrates even after prolonged storage, especially onsmooth substrates such as polymer films or polymer-coated papers.

The novel compositions have the advantage that the resulting crosslinkedorganopolysiloxane films have a low content of extractable constituents.

The novel compositions have the advantage, furthermore, that theresulting crosslinked organopolysiloxane films lead to reproduciblerelease values relative to a wide variety of adhesives.

The novel compositions have the advantage that the crosslinkedorganopolysiloxane films obtained lead to markedly graduated,reproducible release values, which are stable over time, relative to awide variety of adhesives, the graduation of the release valuesdepending essentially on the different quantities of organopolysiloxaneresin (5) present in the novel compositions.

The novel compositions have the advantage that the properties ofcrosslinked organopolysiloxane films depend only slightly, if at all, onthe storage period of the ready-to-use formulation prior tocrosslinking.

In the examples which follow, all parts and percentages are by weightunless specified otherwise. Unless specified otherwise, the followingexamples are carried out at the pressure of the surrounding atmosphere,i.e. at about 1,000 hPa, and at room temperature, i.e. at about 20° C.,or at the temperature which is established when the reactants arecombined at room temperature without additional heating or cooling. Allviscosity data indicated in the examples are intended to relate to atemperature of 25° C.

The iodine number is a meaure of the content of aliphatic carbon-carbonmultiple bonds in a substance and is the number which indicates how manyg of iodine are bonded by 100 g of substance analyzed.

The substrates indicated in the following examples are coated with thenovel organopolysiloxane compositions using a metallic drawing rod, aso-called manual doctor blade, with slow, even guidance, to give aweight per unit area of about 1.5 g/m², or rapidly with uniform pressureusing a glass rod, so that the weight per unit area is about 4 g/m².

The coated substrates are crosslinked while suspended in a convectionoven at the temperatures and for the times indicated in the followingexamples.

The coated substrates are irradiated in a UV apparatus from BeltronXenon Impulslicht GmbH (D-Roedermark) with a 100 watt UV lamp fromPhilips. The distance of the coated substrate from the UV lamp is 8.5cm.

The release values are determined in accordance with FINAT Test No. 10.In this test, the coated substrate has applied to it, directly aftercrosslinking, the respective adhesive, which is pressed on by rollingover two times with the FINAT roller. The laminate is then stored for 20hours at a temperature of 70° C. and a pressure of 70 g/cm². Afterstorage, the release values are determined on a computer pull-offinstrument from Roell and Korthaus (CH-Merlshausen) under a pull-offangle of 180° C. and at a pull-off speed of 300 mm per minute.

The release values are measured relative to rubber adhesives ofdesignation T-4154 and K-7476 and an acrylic adhesive of designationA-7475 (each obtainable commercially from Beiersdorf, D-Hamburg).

In order to assess the completeness of cross-linking of the curedorganosiloxane coatings, the so-called stripe test is employed. In thiscontext, directly after the crosslinking of the organosiloxane coatingon the substrate surface, the dry finger tip is used to draw a stripeabout 25 cm long, rapidly and under uniform pressure, over the siliconelayer. If the crosslinking of the organopolysiloxane film is incomplete,part of the silicone surface is wiped away. This becomes evident as asmear track whose extent is evaluated with ratings from 1 to 6, therating 1 denoting no visible stripe (very good crosslinking), the rating3 denoting a slight stripe and the rating 6 denoting a severe stripe(very poor crosslinking), and the ratings in between being used toindicate further fine graduations in the completeness of crosslinking.

The determination of the so-called residual adhesive force, which islikewise a measure of the completeness of crosslinking of theorganopolysiloxane film, is carried out in accordance with FINAT TestNo. 11. In this test, 65 g/m² glassine paper is coated with the novelorganosiloxane composition, which is then vulcanized, and thesiliconized paper then has applied to it the abovementioned rubberadhesive of designation T-4154 and is then pulled off again inaccordance with FINAT Test No. 10. Using this adhesive, the releasevalue according to FINAT Test No. 10 (release value A) is thendetermined on am acetate film. For comparison, the release value of afresh rubber adhesive on the acetate film is employed (release value B).The residual adhesive force is determined in accordance with thefollowing formula: ##EQU2##

The higher the residual adhesive force value, the more complete thecrosslinking of the organopolysiloxane film.

In order to determine silicone constituents in the crosslinkedorganopolysiloxane coating which are still extractable, a siliconizedpaper strip with an area of 5×20 cm is cut out, using a sharp knife anda template, directly after curing from a 65 g/m² glassine paper coatedwith the novel organopolysiloxane composition. The siliconized paperstrip is then rolled up loosely, placed in a small 25 cm³ sample flaskand treated with 20 ml of methyl isobutyl ketone so that the siliconizedpaper strip is entirely immersed in the extractant. The extraction timeis 10 hours. The silicon content of the extraction solution is thendetermined by means of atomic absorption, permitting calculation of atheoretical silicone add-on A (in g/m²) in accordance with the followingformula:

    silicon content (g/ml)×0.00528=silicone add-on A (g/m.sup.2)

At the same time, X-ray fluorescence is used to determine the siliconeadd-on B (in g/m²) of the unextracted siliconized paper. The extractableconstituents can then be determined in accordance with the followingformula: ##EQU3##

In order to assess the abrasion strength of the crosslinkedorganosiloxane coatings, the siliconized substrate is stretched betweenthumb and index finger. Then, with some force, the finger of the otherhand is used to rub the siliconized substrate several times backward andforward rapidly. If adhesion of the silicone film to the substrate isincomplete, part of the silicone coating becomes detached. The abrasionis assessed in accordance with its extent using ratings from 1 to 6,rating 1 denoting no abrasion, rating 3 denoting slight abrasion andrating 6 denoting severe abrasion, with the ratings in between beingused to indicate further fine graduations in the degree of abrasion.

EXAMPLE 1

58.2 g of a copolymer of trimethylsiloxane, dimethylsiloxane andmethylhydridosiloxane units having a viscosity of 77 mm² /s and acontent of Si-bonded hydrogen of 0.048%, 200 g of a copolymer ofvinyldimethylsiloxane and dimethylsiloxane units having a viscosity of157 mm² /s and an iodine number of 7, 258.2 g of toluene and platinum inthe form of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complexand in a quantity such that the overall mixture has a platinum contentof 6 ppm based on elemental platinum are mixed in the stated sequence.The mixture is then heated with stirring to 90° C. and held at 90° C.for one hour. Then toluene and any other volatile constituents areremoved from the reaction mixture by distillation at a temperature of150° C. and a pressure of 10 hPa. 255.7 g of an organopolysiloxane areobtained which is completely soluble in organic solvents such as tolueneand xylene and has a viscosity of 1656 mm² /s and an iodine number of3.2. Even after storage at 25° C. for 10 weeks, there is no change inthe viscosity of the organopolysiloxane.

EXAMPLE 2

458.5 g of a copolymer of trimethylsiloxane, dimethylsiloxane andmethylhydridosiloxane units having a viscosity of 115 mm² /s and acontent of Si-bonded hydrogen of 0.047%, 270.8 g of a copolymer ofvinyldimethylsiloxane and dimethylsiloxane units having a viscosity of42 mm² /s and an iodine number of 20.9, 270.8 g of a copolymer ofvinyldimethylsiloxane and dimethylsiloxane units having a viscosity of30 mm² /s and an iodine number of 25.7, 428.5 g of toluene and platinumin the form of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxanecomplex and in a quantity such that the overall mixture has a platinumcontent of 3 ppm based on elemental platinum are mixed in the statedsequence. The mixture is then heated with stirring to 90° C. and held at90° C. for one hour. Then toluene and any other volatile constituentsare removed from the reaction mixture by distillation at a temperatureof 150° C. and a pressure of 10 hPa. 975.6 g of an organopolysiloxaneare obtained which is completely soluble in organic solvents such astoluene and xylene and has a viscosity of 3055 mm² /s and an iodinenumber of 7.3. Even after storage at 25° C. for 10 weeks, there is nochange in the viscosity of the organopolysiloxane.

EXAMPLE 3

158 g of the copolymer of trimethylsiloxane, dimethylsiloxane andmethylhydridosiloxane units used in Example 1, 200 g of a copolymer ofvinyldimethylsiloxane and dimethylsiloxane units having a viscosity of30 mm² /s and an iodine number of 22.1 and platinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 7 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. Then any volatile constituents are removed from the reactionmixture by distillation at a temperature of 150° C. and a pressure of 10hPa. 341.3 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 680 mm² /s and an iodine number of 6.75. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane.

EXAMPLE 4

183.3 g of a copolymer of trimethylsiloxane, dimethylsiloxane andmethylhydridosiloxane units having a viscosity of 30 mm² /s and acontent of Si-bonded hydrogen of 0.044%, 100 g each of the copolymers ofvinyldimethylsiloxane and dimethylsiloxane units used in Example 2, andplatinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 7 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. Then any volatile constituents are removed from the reactionmixture by distillation at a temperature of 150° C. and a pressure of 10hPa. 367.9 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 105 mm² /s and an iodine number of 7.1. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane.

EXAMPLE 5

The procedure described in Example 4 is repeated with the modificationthat, instead of 183.3 g of the copolymer of trimethylsiloxane,dimethylsiloxane and methylhydridosiloxane units 281.1 g are employed.468.4 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 266 mm² /s and an iodine number of 2.84. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane

EXAMPLE 6

150 g of a copolymer of trimethylsiloxane, dimethylsiloxane andmethylhydridosiloxane units having a viscosity of 64 mm² /s and acontent of Si-bonded hydrogen of 0.046%, 1.74 g of 1-dodecene andplatinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 12 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. The reaction mixture is then cooled to 50° C., and 63 g ofeach of the copolymers of vinyldimethylsiloxane and dimethylsiloxaneunits used in Example 2 are added. The mixture is then heated to 90° C.and held at 90° C. for one hour. Then any volatile constituents areremoved from the reaction mixture by distillation at a temperature of150° C. and a pressure of 10 hPa. 265.6 g of an organopolysiloxane areobtained which is completely soluble in organic solvents such as tolueneand xylene and has a viscosity of 473 mm² /s and an iodine number of5.3. Even after storage at 25° C. for 10 weeks, there is no change inthe viscosity of the organopolysiloxane. ¹ H-NMR measurements show thatthe terminally unsaturated hydrocarbon has been incorporated chemicallyinto the organosiloxane.

EXAMPLE 7

158 g of a copolymer of dimethylhydridosiloxane, dimethylsiloxane andmethylhydridosiloxane units having a viscosity of 94 mm² /s and acontent of Si-bonded hydrogen of 0.048%, 200 g of the copolymer ofvinyl-dimethylsiloxane and dimethylsiloxane units used in Example 3, andplatinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 7 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. Then any volatile constituents are removed from the reactionmixture by distillation at a temperature of 150° C. and a pressure of 10hPa. 343.4 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 460 mm² /s and an iodine number of 6.9. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane.

EXAMPLE 8

283 g of the copolymer of dimethylhydridosiloxane, dimethylsiloxane andmethylhydridosiloxane units used in Example 7, 25 g of1,3-divinyl-1,1,3,3-tetramethyldisiloxane and platinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 9 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. Then any volatile constituents are removed from the reactionmixture by distillation at a temperature of 150° C. and a pressure of 10hPa. 293.5 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 623 mm² /s and an iodine number of 5.6. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane.

EXAMPLE 9

58.2 g of the copolymer used in Example 7 of dimethylhydridosiloxane,dimethylsiloxane and methylhydridosiloxane units, 200 g of the copolymerused in Example 1 of vinyldimethylsiloxane and dimethylsiloxane units,258 g of toluene and platinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 7 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. Then toluene and any other volatile constituents are removedfrom the reaction mixture by distillation at a temperature of 150° C.and a pressure of 10 hPa. 255.7 g of an organopolysiloxane are obtainedwhich is completely soluble in organic solvents such as toluene andxylene and has a viscosity of 1716 mm² /s and an iodine number of 3.2.Even after storage at 25° C. for 10 weeks, there is no change in theviscosity of the organopolysiloxane.

EXAMPLE 10

132 g of a copolymer of dimethylhydridosiloxane, dimethylsiloxane andmethylhydridosiloxane units having a viscosity of 66 mm² /s and acontent of Si-bonded hydrogen of 0.061%, 100 g each of the copolymers ofvinyldimethylsiloxane and dimethylsiloxane units used in Example 2, andplatinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex and in aquantity such that the overall mixture has a platinum content of 7 ppmbased on elemental platinum are mixed in the stated sequence. Themixture is then heated with stirring to 90° C. and held at 90° C. forone hour. Then any volatile constituents are removed from the reactionmixture by distillation at a temperature of 150° C. and a pressure of 10hPa. 317.4 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 462 mm² /s and an iodine number of 7.7. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane.

EXAMPLE 11

The procedure described in Example 10 is repeated with the modificationthat, instead of 132 g of the copolymer of dimethylhydridosiloxane,dimethylsiloxane and methylhydridosiloxane units 152 g are employed.336.5 g of an organopolysiloxane are obtained which is completelysoluble in organic solvents such as toluene and xylene and has aviscosity of 928 mm² /s and an iodine number of 6.2. Even after storageat 25° C. for 10 weeks, there is no change in the viscosity of theorganopolysiloxane.

EXAMPLE 12

The constituents set out below are mixed to prepare a coatingcomposition I: 100 parts of organopolysiloxane according to Example 3,0.09 part of ethynylcyclohexanol, a copolymer of trimethylsiloxane,dimethylsiloxane and methylhydridosiloxane units having a viscosity of25 mm² /s and a content of Si-bonded hydrogen of 1.62% in a quantitysuch that the molar ratio of the Si-bonded hydrogen atoms to the vinylgroups of the novel organopolysiloxane employed has the value 2, andplatinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in a quantitysuch that the overall mixture has a platinum content of 100 ppm based onelemental platinum.

A coating composition II is prepared in analogy to the coatingcomposition I but with the modification that, instead of 100 parts oforganopolysiloxane according to Example 3, 100 parts oforganopolysiloxane according to Example 7 are employed.

The coating compositions I and II thus prepared are drawn out directlyafter their preparation, using a glass rod, onto 65 g/m² glassine papersto give a weight per unit area of about 4 g/m².

Subsequently, directly after coating, the coated papers are cured at 85°C. and, respectively, at 150° C. for the different times indicated inTable 1 and are assessed by means of the finger stripe test and the testfor abrasion resistance.

In order to determine the release values and the residual adhesiveforce, the coated papers are cured at 150° C. for 5 seconds.

The results are given in Table 1.

COMPARISON EXAMPLE 1

The procedure described in Example 12 is repeated with the modificationthat the coating composition employed includes, instead of 100 parts ofthe organopolysiloxane according to Example 3, 100 parts of a linearcopolymer of vinyldimethylsiloxane and dimethylsiloxane units having aviscosity of 195 mm² /s and an iodine number of 6.8 (coating compositionComp1).

The results are given in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Crosslinking temperature                                                      85° C.    150° C.                                                                    Residual                                                                           Release values                                      Crosslinking time [s]                                                                              adhesive                                                                           [cN/cm]                                             Compo-                                                                            8  10  12 15 4   force                                                                              Adhesive                                            sition                                                                            Finger stripe test                                                                             [%]  T-4154                                                                            K-7476                                                                             A-7475                                     __________________________________________________________________________    I   2-3                                                                              2   1-2                                                                              1  1   119  2.9 7.1  6.9                                          II 2 1 1 1 1 121 5.0 12.7 7.8                                                 Comp 1 3 2-3 2 1 1 111 3.1 11.7 7.3                                         __________________________________________________________________________

At the curing time at which the coated papers were assessed with therating 1 in the finger stripe test, the test for abrasion resistance,which is carried out directly after curing, is also assessed with therating 1.

EXAMPLE 13

The procedure described in Example 12 is repeated with the modificationthat, instead of the copolymer of trimethylsiloxane, dimethylsiloxaneand methylhydridosiloxane units having a viscosity of 25 mm² /s and acontent of Si-bonded hydrogen of 1.62%, a copolymer oftrimethylsiloxane, dimethylsiloxane and methylhydridosiloxane unitshaving a viscosity of 39 mm² /s and a content of Si-bonded hydrogen of1.17% is employed, likewise in a quantity such that the molar ratio ofthe Si-bonded hydrogen atoms to the vinyl groups of theorganopolysiloxane prepared according to Example 3 or, respectively, toExample 7 has the value 2. This gives the coating composition III, whichis based on the organopolysiloxane according to Example 3, and thecoating composition IV, which is based on the organopolysiloxaneaccording to Example 7. The results are given in Table 2.

COMPARISON EXAMPLE 2

The procedure described in Comparison Example 1 is repeated with themodification that, instead of the copolymer of trimethylsiloxane,dimethylsiloxane and methylhydridosiloxane units having a viscosity of25 mm² /s and a content of Si-bonded hydrogen of 1.62%, a copolymer oftrimethylsiloxane, dimethylsiloxane and methylhydridosiloxane unitshaving a viscosity of 39 mm² /s and a content of Si-bonded hydrogen of1.17% is employed, likewise in a quantity such that the molar ratio ofthe Si-bonded hydrogen atoms to the vinyl groups of the linearorganopolysiloxane employed has the value 2 (coating composition Comp2).The results are given in Table 2.

                  TABLE 2                                                         ______________________________________                                                                  Abrasion resistance                                     after a curing                                                              Crosslinking temperature  time of 10 seconds at                               85° C. Residual a temperature of 85° C.                       Crosslinking time [s]                                                                          adhesive directly  after                                     Compo-                                                                              4      6      8    10  force  after   three                             sition                                                                              Finger stripe test                                                                           [%]      curing  days                                    ______________________________________                                        III   4      1-2    1    1   119    1       1                                   IV 3 1 1 1 121 1 2                                                            Comp 2 --* 3 1-2 1 111 1 3                                                  ______________________________________                                         *No measurement results present                                          

EXAMPLE 14

The coating compositions I and II according to Example 12 are each drawnout, directly after their preparation and, respectively, after a storageperiod of 2 hours, using a hand doctor blade onto 65 g/m² glassine paperto give a weight per unit area of in each case about 1.5 g/m².

Subsequently, directly after coating, the coated papers are cured at 85°C. for different periods and, directly after curing or, respectively,after different storage of the cured coated papers, the extractablesilicone constituents are determined.

The results are given in Table 3.

In the case of coating composition II the value for the extractableconstituents on coating directly after preparation of the coatingcomposition and directly after curing at a crosslinking temperature of150° C. and a curing time of 5 seconds is 1.9%.

                                      TABLE 3                                     __________________________________________________________________________    Storage time of the                                                             composition following Storage time of the composition:                        preparation in hours 0 Hours                                                0            2         Crosslinking time: 12 s                                Crosslinking time [s]  Storage time of the cured paper [min]                  Compo-                                                                            16 20 30 16 20  30 5  15 60  120                                                                              240                                       sition                                                                            Extractable constituents [%]                                              __________________________________________________________________________    I   11.6                                                                             10.4                                                                             8.7                                                                              17.5                                                                             16.0                                                                              9.7                                                                              12.1                                                                             10.9                                                                             7.9 8.2                                                                              7.4                                         II 7.2 5.3 3.9 20.4 12.6 9.4 10.2 8.2 3.6 3.1 2.1                             Comp 1 15.6 12.4 7.9 40.7 24.8 16.3 30.1 17.2 11.3 7.9 6.0                  __________________________________________________________________________

COMPARISON EXAMPLE 3

The procedure described in Example 14 is repeated with the modificationthat, instead of the coating composition I or II, the coatingcomposition Comp1 from Comparison Example 1 is employed. The results aregiven in Table 3.

The value for the extractable constituents on coating immediately afterpreparation of the coating composition and immediately after curing at acrosslinking temperature of 150° C. and a curing time of 5 seconds is3.4%.

EXAMPLE 15

The coating compositions I and II according to Example 12 are drawn out,in each case directly after their preparation, using a glass rod ontothe substrates listed below, to give a weight per unit area of in eachcase about 4 g/m².

Substrate (a): polyethylene-laminated paper

Substrate (b): low-pressure polyethylene film

Substrate (c): high-pressure polyethylene film

Substrate (d): polyester film

Substrate (e): clay-coated paper with a weight of 140 g/m²

Substrate (f): clay-coated paper with a weight of 80 g/m²

Substrate (g): clay-coated paper with a weight of 135 g/m²

Substrate (h): clay-coated paper with a weight of 87 g/m²

Subsequently, directly after coating, the coated substrates are cured at₈₅ ° C. for a period of time which differs depending on the substrateused. Then, depending on the storage period of the cured coatedsubstrates, the abrasion resistance is assessed. The results are givenin Table 4.

COMPARISON EXAMPLE 4

The procedure described in Example 15 is repeated with the modificationthat, instead of the coating composition I or II, the coatingcomposition Comp1 from Comparison Example 1 is employed.

The results are given in Table 4.

                  TABLE 4                                                         ______________________________________                                                    Substrate                                                                       (a)   (b)   (c) (d) (e)  (f)  (g) (h)                           Storage time of                                                                             Crosslinking time [s]                                           Compo-                                                                              the cured coated                                                                          30    15  15  15  30   20   30  20                          sition                                                                              substrates in days                                                                        Abrasion resistance                                         ______________________________________                                        I     0           1     1   1   1   1    1    1   1                              2 1 1 1 1 1 1 1 1                                                             10 1 1 1 1 2 1 1 1-2                                                          28 1 1 1 1 2 1 1 1-2                                                          56 1 1 1 1 2 1 1 1-2                                                         II 0 1 1 1 1 1 1 1 2-3                                                         2 1 1 1 1 1 1 1 3                                                             10 1 1 1 1 4 1-2 1 3                                                          28 1 1 1 1 4 1-2 1 3-4                                                        56 1 1 1 1 5 2 1 4                                                           Comp 1 0 1 1 1 1 1 1 1 1-2                                                     2 1 1 1 1 1 1 1 2                                                             10 1 3 1 1 4-5 3 1 2                                                          28 1 3 1 2 5 3 1 2-3                                                          56 1 3 1 2 5 4 1 2-3                                                       ______________________________________                                    

EXAMPLE 16

The coating composition II according to Example 12 is drawn out directlyafter its preparation, using a glass rod, onto 65 g/m² parchment paperto give a weight per unit area of about 4 g/m². Subsequently, directlyafter coating, the coated paper is irradiated in a UV apparatus fordifferent periods and is assessed by means of the finger stripe test. Inthe course of irradiation the coated paper heats up to about 85° C. Theresults are given in Table 5.

COMPARISON EXAMPLE 5

The procedure described in Example 16 is repeated with the modificationthat, instead of the coating composition II, the coating compositionComp1 from Comparison Example 1 is employed. The results are given inTable 5.

                  TABLE 5                                                         ______________________________________                                                      Irradiation time in seconds                                                   0.7     1.4                                                     Coating composition                                                                           Finger stripe test                                            II              1-2       1                                                     Comp 1 2   1-2                                                              ______________________________________                                    

EXAMPLE 17

Preparation of MQ resin powder A:

A 70% strength solution in toluene of an MQ resin consisting of (CH₃)₃SiO_(1/2), (CH₃)₂ (CH₂ ═CH)SiO_(1/2) and SiO_(4/2) units in a molarratio of 0.70:0.10:1 is used to prepare, by the process described in theinitially cited German application with the file reference 19502034.0, aflowable resin powder having a mean particle diameter (D₅₀ value) of 155μm, a bulk density of 460 kg/m³ and a mean toluene content of 0.07%,based on the weight of the resin powder.

The constituents set out below are mixed to prepare a coatingcomposition V: 80 parts of organopolysiloxane according to Example 3 and20 parts of the above-described MQ resin powder, 0.09 part ofethynylcyclohexanol, a copolymer of trimethylsiloxane, dimethylsiloxaneand methylhydridosiloxane units having a viscosity of 25 mm² /s and acontent of Si-bonded hydrogen of 1.62% in a quantity such that the molarratio of the Si-bonded hydrogen atoms to the vinyl groups of the novelorganopolysiloxane employed and of the siloxane resin has the value 2,and platinum in the form of aplatinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in a quantitysuch that the overall mixture has a platinum content of 100 ppm based onelemental platinum.

A coating composition VI is prepared in analogy to the coatingcomposition V but with the modification that, instead of 80 parts oforganopolysiloxane according to Example 3, 80 parts oforganopolysiloxane according to Example 7 are employed.

The subsequent procedure is as described in Example 12. The results aregiven in Table 6.

COMPARISON EXAMPLE 6

The procedure described in Example 17 is repeated with the modificationthat the coating composition employed includes, instead of 80 parts ofthe organopolysiloxane according to Example 3, 100 parts of a linearcopolymer of vinyldimethylsiloxane and dimethylsiloxane units having aviscosity of 195 mm² /s and an iodine number of 6.8 (coating compositionComp3).

The results are given in Table 6.

At the curing time at which the coated papers were assessed with therating 1 in the finger stripe test, the test for abrasion resistance,which is carried out directly after curing, is also assessed with therating 1.

                  TABLE 6                                                         ______________________________________                                        Crosslinking                                                                    temperature [° C.]                                                   85            150    Resi-                                                    Crosslinking     dual ad-                                                                              Release values                                         time in seconds hesive [cN/cm]                                              Compo-                                                                              12     15     20  4    force Adhesive                                   sition                                                                              Finger stripe test                                                                           [%]     T-4154                                                                              K-7476                                                                              A-7475                               ______________________________________                                        V     2      1-2    1   1    115   15.8  13.1  13.6                             VI 1-2 1-2 1 1 122 24.8 21.7 13.9                                             Comp 3 2-3 1-2 1 1 121 17.9 20.6 13.3                                       ______________________________________                                    

EXAMPLE 18

The coating composition VI according to Example 17 is drawn out,directly after its preparation, using a hand doctor blade, onto 65 g/m²glassine paper to give a weight per unit area of about 1.5 g/m².

Subsequently, directly after coating, the coated paper is cured for 5seconds at 150° C. and, directly after curing, the extractable siliconeconstituents are determined. The value is 2.9%.

What is claimed is:
 1. An organopolysiloxane containing aliphaticallyunsaturated radicals, which is soluble in organic solvents selected fromthe group consisting of xylenes and toluene to an extent of at least 80percent by weight, at a temperature of 25° C. and a pressure of from 900to 1100 hPa, and comprises at least one unit of the formula

    R.sup.1.sub.a R.sub.2-a SiO.sub.2/2                        (I),

at least one unit of the formula

    R.sup.1.sub.b R.sub.3-b SiO.sub.1/2                        (II),

at least one unit of the formula

    O.sub.1/2 R.sub.2 SiO.sub.x YRSiO.sub.2/2                  (III)

and, optionally, at least one unit of the formula

    O.sub.1/2 R.sub.2 SiO.sub.x YR.sub.2 SiO.sub.1/2           (IV),

where R can be identical or different and is a monovalent, substitutedor unsubstituted, SiC-bonded, aliphatically saturated hydrocarbonradical, R¹ can be identical or different and is a monovalent,SiC-bonded, substituted or unsubstituted, aliphatically unsaturatedhydrocarbon radical, a is 0, 1 or 2, b is 0, 1, 2 or 3, x is 0 or 1 andY is a radical --(CR³ ₂)_(n) CHR³ -- with at least two carbon atoms,where n is 0 or an integer from 1 to 3 and R³ is a hydrogen atom or isas defined for R,with the proviso that the organopolysiloxane includesat least one unit of the formula (II) where b is not
 0. 2. Anorganopolysiloxane as claimed in claim 1, wherein radical R¹ is thevinyl radical.
 3. An organopolysiloxane is claimed in claim 1, whereinradical Y is --CH₂ --CH₂ or --CH(CH₃)--.
 4. An organopolysiloxane asclaimed in claim 1, which consists of units of the formula (I), (II),(III) and, optionally, (IV).
 5. A process for preparing anorganopolysiloxane as claimed in claim 1, which comprises reactinglinear organosiloxanes A consisting of at least one unit of the formula

    R.sup.4.sub.c R.sup.5.sub.2-c SiO.sub.2/2                  (V),

and/or at least one unit of the formula

    R.sup.4.sub.d R.sup.5.sub.3-d SiO.sub.1/2                  (VI),

where R⁴ can be identical or different and is as defined for R¹, R⁵ canbe identical or different and is as defined for R, c is 0, 1 or 2, and dis 0, 1, 2 or 3,with the proviso that organosiloxanes A possess at leastone radical R⁴ and that there is at least one organosiloxane A having 2units of the formula (VI) where d is not 0, with linear or cyclicorganosiloxane B consisting of at least one unit of the formula

    H.sub.f R.sup.7.sub.g R.sup.6.sub.3-f-g SiO.sub.1/2        (VIII),

and/or at least one unit of the formula

    H.sub.e R.sup.6.sub.2-e SiO.sub.2/2                        (VII),

where R⁶ can be identical or different and is as defined for R, R⁷ is asdefined for R¹, e is 0 or 1, f is 0 or 1, and g is 0, 1, 2 or 3,with theproviso that the sum g+f is less than or equal to 3 and thatorganosiloxane B has at least one unit of the formula (VII) where e is1, and, optionally, with hydrocarbons C containing aliphaticcarbon-carbon multiple bonds and, optionally, in the presence of inertorganic solvent D, in the presence of a catalyst E which promotes theaddition of Si-bonded hydrogen onto aliphatic multiple bond, with theproviso that in the unreacted mixture of starting materials the molarratio of the units of the formula (VI) where d is not 0 to the Si-bondedhydrogen atoms present in the units of the formula (VII) is at least1.3:1.
 6. A crosslinkable organopolysiloxane composition whichcomprises(1) an organopolysiloxane as claimed in claim 1, (2) one ormore organosiloxanes containing Si-bonded hydrogen, (3) one or morecatalysts which promote the addition of Si-bonded hydrogen ontoaliphatic multiple bond.
 7. An organopolysiloxane composition as claimedin claim 6, wherein the organosiloxanes (2) containing Si-bondedhydrogen atoms used are linear, cyclic or branched organopolysiloxanescomprising units of the formula

    R.sup.8.sub.h H.sub.i SiO.sub.4-h-i/2                      (IX)

where R⁸ can be identical or different and is as defined above for R, his 0, 1, 2 or 3, and i is 0, 1 or 2,with the proviso that the sum of h+iis less than or equal to 3 and that there are on average at least twoSi-bonded hydrogen atoms per molecule.
 8. An organopolysiloxanecomposition as claimed in claim 6, wherein siloxane (2) is employed inquantities of from 0.7 to 5 mol of Si-bonded hydrogen, based on 1 mol ofaliphatic carbon-carbon multiple bond in the organopolysiloxane (1). 9.An organopolysiloxane composition as claimed in claim 6, which consistsof the constituents (1), (2), (3) and, optionally one or more of thefollowing: (4) one or more inhibitors, (5) one or moreorganopolysiloxane resins, (6) one or more linear organopolysiloxanescontaining aliphatic carbon-carbon multiple bonds, (7) one or morehydrocarbons containing aliphatic carbon-carbon multiple bonds, and oneor more organic solvents.
 10. A crosslinkable organopolysiloxanecomposition which comprises:(1) an organopolysiloxane as prepared inclaim 5, (2) one or more organosiloxanes containing Si-bonded hydrogen,(3) one or more catalysts which promote the addition of Si-bondedhydrogen onto aliphatic multiple bonds.
 11. An organopolysiloxanecomposition as claimed in claim 10, wherein the organosiloxanes (2)containing Si-bonded hydrogen atoms used are linear, cyclic or branchedorganopolysiloxanes comprising units of the formula ##EQU4## where R⁸can be identical or different and is as defined above for R,h is 0, 1, 2or 3, and i is 0, 1 or2,with the proviso that the sum of h+i is lessthan or equal to 3 and that there are on average at least two Si-bondedhydrogen atoms per molecule.